Jason Momoa is about to unleash his inner barbarian so you’d best find a safe seat. Things are going to get bloody.

After 12 years as a steadily working television actor, the Hawaii-born Momoa will star in a pair of sword-swinging epics that he believes will redefine his career: "Game of Thrones," the sprawling HBO series that premieres Sunday, and a new version of "Conan the Barbarian," a big-budget movie scheduled for release in August.

"It’s been a lot of work but I’m on the forefront of something huge," the 31-year-old actor said by telephone from Los Angeles.

The two projects have kept him busy for nearly three years. The part of Khal Drogo, the fiercest warlord in "Game of Thrones," required an emotional and physical transformation for Momoa, a former model whose previous roles were as a lifeguard in "Baywatch Hawaii," a bartender in "North Shore" and a dreadlock-sporting alien in "Stargate: Atlantis."

When Momoa auditioned, the 6-foot-4, part-Hawaiian actor politely told a pair of HBO producers — "two small haole ladies" — that he was going to try something different. Then he got in their faces with a haka — a Polynesian war chant.

"I said, ‘Don’t be scared, I am not going to kill you,’ and they were just smiling," Momoa said. "And I went off."

People in other offices thought something was wrong, but his intensity sealed the deal for Momoa.

"I just wanted to show them that if you are going to look any great king or warrior in the eye, here is what their soul is," he said. "It’s a fierce thing to be in front of, if you really put your heart and soul into it."

"Game of Thrones" is based on the fantasy book series "A Song of Fire and Ice" by George R.R. Martin and follows nearly two dozen characters in a world of kings, queens, knights, liars, sex and intrigue. It was shot in Northern Ireland and Malta.

MOMOA WANTED the part of Khal Drogo more than anything else he’s ever done.

"I have never been so consumed and passionate about a role," he said. "It was a real breakthrough in my career."

He hit the gym and packed on 35 pounds of muscle; Momoa weighed 250 pounds for the series. He also had to learn to speak a fictional language well enough to sound convincing during an extended speech.

"It’s a great war speech in front of a big fire," Momoa said. "This is the greatest scene I have ever done in my life. You never get to say these words on TV. You don’t get to say, ‘I am going to rape your women and bring their children back as slaves.’"

But that level of intensity had a dark side: He would act with such aggression that he would leave the actress who plays the wife of Khal Drogo — Emilia Clarke — in tears. "It is exhilarating and scary and fearful," he said.

THE HAKA that Momoa performed inside HBO’s Santa Monica headquarters also helped him land the part of Conan. He was asked to perform it for a second group that included a casting director who was involved with the "Conan" film.

"Right after that, he called up his people and said, ‘I got your next Conan,’" Momoa said.

Conan was created in the 1930s by American author Robert E. Howard. Momoa grew up reading the Conan stories in paperbacks and comic books and was a huge fan of the stylized artwork that was an inseparable part of the character: the muscled barbarian slaying demons and rescuing busty, half-naked women.

In the early 1980s, Arnold Schwarzenegger brought "Conan the Barbarian" to the big screen, but don’t compare the two efforts, Momoa said.

"I am not remaking an Arnold movie," he said. "We are rebooting something that has so many stories by Robert E. Howard that haven’t been told. When you take on a character, you want to build it yourself."

Momoa has seen some of his "Conan," which was directed by Marcus Dispel, and he called it amazing. He’s contracted to do two sequels, but only if this one does well.

"There are a lot of roles on the horizon," he said. "If ‘Conan’ goes well you will see a lot more of me. It is a dream come true to be on the big screen."